Reverse string

[JTan]

//I try to duplicate a string. However when I try to print
//it out, there would always be some weird characters
//behind. May I know what is the reason?

/*This is part of the codes from the main function*/

case '5'rintf("\tThe duplicate string is: %s.\n",duplicate(text));
break;

/*Duplicate the new string*/
char* duplicate(char *text)
{

return strcat(text,text);

}//duplicate

 

[Guest_imported]

strcat reference in MSDN says:

No overflow checking is performed when strings are copied or appended. The behavior of strcat is undefined if the source and destination strings overlap.

 

[icici]

In case u are concatnating the two arrays(texts), the length of resultant array should be greater than or equal to the length of the two arrays.

TRY THIS

#include <iostream.h>
#include <string.h>
#include <conio.h>



#define RESET(x) memset(x,0,sizeof(x))

void main(void)
{char first_array[20], second_array_30], result_array[100];

RESET(first_array);
RESET(second_array);
RESET(result_array);

strcat(first_array,&quot;MY FIRST ARRAY - 1 &quot;
strcat(second_array,&quot;SECOND ARRAY- 2&quot;

strcat(result_array,first_array);
strcat(result_array,second_array);

clrscr(); gotoxy(20,10);
cprintf(&quot;%s&quot;,result_array);
cin.get(); // press Enter key


}

 

[fireblade]

I would use:

/*Duplicate the new string*/
char* duplicate(char *text)
{
char *text2;

text2 = (char *) malloc (strlen (text)+1);
sprintf (text2, text);
return text2;

}//duplicate

As far as I remember strcat doesn't add a zero byte to
terminate the string but sprintf does. When a non-zero byte
terminated string is printed, garbage nearly always results until a zero is found somewhere in memory. However you do it, remember to delete the duplicated string; there isn't any provision in your code (or mine) to do it !

 

[fireblade]

oops, that should have been

sprintf (text2, &quot;%s&quot;, text);

 

[andrew23]

/*Duplicate the new string*/
char* duplicate(char text[])
{
char text2[50];

strcpy (text2, text);

return strcat(text2,text);

}


char text2[100];

strcpy (text2, duplicate(text));

printf(&quot;\tThe duplicated string is: %s.\n&quot;, text2);



x-)I don't really get what you mean, is that what you want?

Andrew Lim

Trying and exploring is adventuring